Mexico kept up its 100 per cent record in CONCACAF World Cup qualifying following a 3-1 win over El Salvador on Friday.

El Salvador - needing a win to keep its hopes of making the 2018 World Cup alive - led 1-0 going into the half-time break.

But the Mexicans, who had already qualified for the next round, proved too strong in the second half, scoring twice early on to seal the victory at the Estadio Cuscatlan in Sal Salvador. 

An Alexander Larin penalty put the Salvadorians ahead, before Hector Moreno levelled things up seven minutes into the second period. 

Angel Sepulveda then put Mexico ahead five minutes later, with Juan Carlos Osorio's men scoring a third through Raul Jimenez in a routine win. 

However, it did not appear as if it were heading that way following the first 45 minutes. El Salvador came out with attacking intent, knowing only a win would do if it was to reach the fifth round of World Cup qualifying. 

It had the Mexicans rattled, and a handball inside the box from Jorge Torres Nilo gifted the home side a spot-kick.

Larin made no mistake from the spot, putting El Salvador ahead with a cool and collected finish in the 24th minute.

The home side almost doubled its advantage in the 28th minute but could not properly capitalise on a Rafael Marquez mistake in defence. 

It continued to attack and create chances as Mexico sat back and defended, with any foray forward for the visitor ending in disappointment. But it came out for the second half a completely different side, asserting its dominance early with a crucial goal. 

Moreno's finish from a set-piece drew Mexico level, and only a few minutes later Sepulveda put it in front with a clinical header from an inch-perfect cross. 

It continued to be all Mexico from that point onwards, with Benfica's Jimenez stepping up to convert its third from the penalty spot after Sepulveda was fouled in the area. 

El Salvador attempted to reduce the deficit but could not penetrate the Mexico defence which has conceded just once in five games. 

The win sees Mexico extend its lead atop Group A to eight points over Honduras, with just one game left to play in the fourth round of qualifying. 

El Salvador, meanwhile, are unable to progress any further, while Canada are on the brink of elimination.